U.S. Pat. No. 5,897,515 discloses an ankle-foot orthosis, comprising a frame of thin flexible material extending over the front of the lower leg, anterior of the lateral ankle and beneath the part of the sole of the foot and a supporting portion of rigid material extending over a narrow part of the front of the lower leg, anterior of the lateral ankle and beneath the part of the sole of the foot. The disclosed orthosis may be worn under the patients ordinary clothes and shoes.
U.S. Pat. No. 2,949,111 discloses a drop-foot brace comprising a supporting sole member to be placed into a shoe and beneath the foot of a handicapped person; a leg embracing member releasably applicable to the leg of said person: a bundle of closely adjacent flat springs and means for connecting the sole member to a lower end of the bundle and means for connecting an upper end of said bundle to the leg embracing member.
The orthoses disclosed in prior art usually refers to orthoses used by persons with severe drop foot or persons having severe muscle weakness in the lower extremities. These orthoses comprise a supporting portion of rigid material extending over a region between a strut on the lower leg and a foot plate. Due to the supporting portion these orthoses provide a strong support but may also be experienced as too rigid by some users, and further the supporting portion is sensitive to wear and tear during walking and may break, especially when used by heavy and very active persons.
There is a need for an improved ankle-foot orthosis to be used by persons having a milder drop foot or a lesser muscle weakness and thus do not need an orthosis as stiff as those disclosed by prior art. Since it is easier for these persons to walk than for persons having a severe drop foot, an improved ankle-foot orthosis with improved wear comfort is desired for these users. Such an ankle-foot orthosis is disclosed in the present invention.